The need for simple and practical means of obtaining girth adjustment in footwear is acknowledged in the shoe industry and growing as continually more shoe offerings are being limited by marketing economics to single widths for each size length. Studies, including those of the U.S. Army QMC, have shown that such single width shoes fit less than one third of the public, and this fraction diminishes still further with the dynamic girth changes experienced by a foot principally from the normal changes in fluid accumulation in the extremities. Such changes are quite significant, usually averaging 11/2 full width increments or `sizes` on a daily basis, with appreciably greater variations being experienced with changes in weather, altitude, or the wearer's physical condition.
To date, the most popular method of girth adjustment is by the shoelace, which affords moderate adjustability in the waist and instep region, but rarely extends to the ball area where lacing or buckle or hook and loop fastener arrangements can be uncomfortable due to the continual flexing thereof during the stride.
The shoes disclosed in U.S. Pat. Nos. 3,541,708 and 3,686,777 proved impractical due to their complexity and resulting high costs. U.S. Pat. No. 3,404,468, however, of which this invention is an improvement, combined simplicity with a most comfortable end product. The '468 shoe, however, proved to be only marginally marketable due to the unacceptable appearance of the sides of the shoe where the upper was not directly attached to the bottom, as well as the tendency of the design to trap pebbles and other debris between the upper and the sole elements.
Past attempts to utilize hook and loop-type detachable fasteners in shoes have been many and varied. For instance, U.S. Pat. No. 2,952,925 discloses the use of stretch-type material for adjusting the width of shoe uppers in combination with a two-part shank for varying the length of the shoe. The two shank portions are detachably connected by a hook and loop type touch fastener. U.S. Pat. No. 3,618,235 discloses the use of a split toe section of a shoe and a tongue-like element, secured to the front of the toe and detachably connected to the shoe by a Velcro fastening means, to cover the opening in the split toe section. U.S. Pat. No. 4,279,083 discloses the use of a hook and loop detachable fastening means to attach a complete replaceable sole to a shoe body.
Past attempts to deal with the girth adjustment problem have not proven commercially viable, primarily because the attachment means were not completely invisible when the shoe was worn. The unattractiveness of the attachment means and the lack of substantial invisibility of them has caused them to be non-competitive with most popular conventionally styled footwear.
Accordingly, it is one of the objects of the present invention to provide a shoe width girth adjustment in all of the critical fitting areas of a shoe including the midportion areas of ball, waist, and instep. It is an object to provide an adjustment means which is substantially completely hidden so it does not detract from the appearance and styling potential of the shoe. It is still another object to provide an adjustment means which is manually adjustable by the wearer when the shoe is on the foot to provide proper fit.